The feedback endpoints use `ticket_type` to decide what to display and
whether or not a ticket should be escalated. We were using the
ticket_type as the value for the Zendesk ticket_type. However, the Zendesk
API accepts 4 values for its ticket_type and these are different from
the ticket_type values we use in our code.
This change converts the Notify ticket_type value to a valid Zendesk
ticket_type value when creating a Notify feedback ticket.